ASX-listed explorer, Impact Minerals, has returned high-grade, near-surface platinum group elements, or “PGE” and base metals drill results from the Plat Central prospect at its Broken Hill project in NSW. The stand-out intercept was 1m going a scintillating 22.7 grams per tonne 7PGE, 3.3 per cent nickel, one per cent copper, 23 g/t silver and 755 g/t cobalt from 62m.
Other notable assays included 7m at 3.8 g/t 7PGE, 0.6 per cent copper, 0.5 per cent nickel, 9.4 g/t silver and 167 g/t cobalt from 53m including 1m at 6.3 g/t 7PGE, 1.2 per cent copper, 0.8 per cent nickel, 19 g/t silver and 229 g/t cobalt from 58m.
Perth-based Impact says the RC drill hits were in line with expectations following an earlier in-field first-pass geochemical program and confirm near-surface high-grade nickel-copper-PGE mineralisation in the recently discovered basal channel at Plat Central.
The geochemical work involved taking measurements of nickel and copper values with a portable X-ray fluorescence, or “XRF” gun. The hand-held XRF instrument also supported the company’s “breakthrough” proprietary geochemical ratio, which it says shows an exceptional positive correlation with or is a predictor of PGE grades.
The company recently identified a specific multi-metal ratio exploration tool that appears to predict PGE grades and can be read with a hand-held XRF instrument as drilling progresses, offering a possible vector towards higher-grade mineralised zones. It says the data generated by portable XRF guns is considered of sufficient accuracy and precision, versus laboratory assay data, to be used to calculate the ratio in the field to guide drilling programs.
Impact suggests the vector may provide a method to help overcome one of the main exploration challenges the company and previous explorers have faced at the project. The challenge, it says, is being able to discriminate and rank the numerous high-grade drill intercepts spread over many hundreds of metres which have proved difficult to track with drill rigs.
Plat Central’s high-grade mineralisation is associated with disseminated to blebby sulphide mineralisation within a Kambalda-style channel. The mineralisation sits at the base of the host ultramafic rocks and was discovered by drilling guided exclusively by the ratio. According to Impact, the mineralised part of the channel is approximately 25m to 30m wide and between one metre and 7m thick.
Further drilling has been completed and is also under way.
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By Matt Birney
